1 . Field of the Invention
The present invention relates to a control device, an image forming apparatus, a printing system, a control method, and a control program, and more particularly to a control device for controlling an image forming apparatus, an image forming apparatus controlled by the same, a printing system including them, and a control method and a control program executed therein.
2 . Description of the Related Art
In recent years, a printer or other image forming apparatus enters a state unready for printing and consuming less power (hereinafter, referred to as “sleep mode”) in order to decrease power consumption if it does not operate for a predetermined period of time. The image forming apparatus, in receipt of printer data from a computer, returns from the sleep mode to a state ready for printing (hereinafter, referred to as “standby mode”), to print out the print data. A certain time is required for switching from the sleep mode to the standby mode, which increases the time until the printing is finished. To address this problem, there is known a technique to transmit a command (hereinafter, referred to as “wake-up command”) to cause the apparatus to return to the standby mode before setting for printing is made by the computer. The wake-up command is transmitted, e.g., upon activation of a printer driver.
Meanwhile, there is known an image forming apparatus provided with a so-called confidential printing function, wherein upon reception of print data from a computer, the print data is temporarily stored without being printed, and thereafter, it is printed on the condition that there is an instruction from a user. This is because the user who instructed confidential printing may not instruct the image forming apparatus to print the same immediately. If the operating mode is switched from the sleep mode to the standby mode upon reception of the print data for confidential printing, power may be wasted in the image forming apparatus until (and after) it attains the standby mode. The same applies to the case of transmitting a wake-up command.
When the image forming apparatus is in the sleep mode, preparation for returning to the standby mode is initiated only after the instruction to print the print data for confidential printing is input to an operation portion. This would increase the waiting time, in addition to the printing time of the image forming apparatus, to wait for the operating mode to be switched from the sleep mode to the standby mode.